Process for reforming surface of substrate, reformed substrate and apparatus for the same

ABSTRACT

Sputtering particles are deposited immediately after activating a surface of a substrate composed of a carbon-containing material. Accordingly, a process for reforming a surface of a substrate, a substrate with a reformed surface, and an apparatus therefor are provided in which the depositability and adhesiveness of the sputtering particles are improved. A vacuum ultraviolet light is generated by a laser beam. A surface of a substrate composed of a carbon-containing material is exposed to the generated vacuum ultraviolet light. As a result, the surface of the substrate is activated. Simultaneously therewith, a sputtering particles-generating device generates sputtering particles, such as neutral atoms, ions and clusters. The resultant sputtering particles are deposited on the activated surface of the substrate. Since the sputtering particles are deposited immediately after the surface of the substrate is activated, they are adhered firmly on the surface of the substrate.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a process for reforming asurface of a substrate composed of a carbon-containing material such asa resinous substrate, process which gives the surface a variety ofcharacteristics such as physical and chemical characteristics. Moreover,it relates to a reformed substrate and an apparatus for the same.

[0003] 2. Description of the Related Art

[0004] Conventionally, as techniques for reforming a surface of resinoussubstrates, the following processes are proposed. For example, resinoussubstrates are exposed to X-rays or ultraviolet lights, which resultfrom synchronized orbital radiation. Alternatively, resinous substratesare exposed to ultraviolet lights to activate the surface by usingultraviolet lamps (see Japanese Unexamined Patent Publication (KOKAI)No. 2001-316,485). After the resinous substrates are exposed to X-raysor ultraviolet lights, they are subjected to additional treatments inair or in gas atmospheres depending on their applications.

[0005] However, in the above-described conventional technologies, sincethe surface of the resinous substrates, which are activated by beingexposed to emitted lights, is varied with time, or since it is exposedto gas atmospheres, it has been deactivated. Thereafter, the resinoussubstrates are subjected to additional treatments depending on theapplications. Accordingly, there is a problem in that the advantagesresulting from the exposure to X-rays might be diminished. Moreover,facilities for generating synchronized orbital radiation are large-sizedfacilities, and are mostly used in a time-sharing manner. Consequently,there arises a problem in that it is difficult to develop materials byusing many samples by trial and error. On the other hand, in theexposure to ultraviolet lamps for mainly generating ultraviolet lightswhose wavelength is 200 nm or more, the ultraviolet lights are absorbedby resinous surfaces with an absorptivity decreased by a factor of{fraction (1/100)} or less, compared with a vacuum ultraviolet lightwhose wavelength falls in a range of from 50 nm to 100 nm. As a result,there is a problem in that the advantage resulting from the activationis effected extremely less.

[0006] The present invention has been developed in view of theabove-described circumstances. It is therefore an object of the presentinvention to provide a process for reforming a surface of substrate bywhich the various characteristics of the surface are improved such asthe depositability, adhesiveness, scratch resistance, dent resistance,ozone resistance, yellowing preventiveness, grooming resistance, dirtresistance, water repellency, hydrophilicity, mildewproofness,frictional property, stainability, printability, writability andlubricative property. And also, improving the electrical conductivity ofthe substrate by the present invention enables us to sprayelectrostatically. Moreover, it is a further object of the presentinvention to provide a reformed substrate provided with the upgradedcharacteristics, and an apparatus for the same.

SUMMARY OF THE INVENTION

[0007] In a first aspect of the present invention, a process accordingto the present invention is adapted for reforming a surface of asubstrate composed of a carbon-containing material, and comprises thestep of: exposing a surface of a substrate to a vacuum ultravioletlight, and depositing sputtering particles on the surface of thesubstrate.

[0008] When the surface of the substrate composed of a carbon-materialis exposed to the vacuum ultraviolet light which is absorbed greatly bycarbon-containing materials, the p-shell electrons, the outer shellelectrons in carbon atoms, are excited or ionized at the substratesurface so that the molecular bonds are destroyed to activate thesubstrate surface composed of a carbon-containing material. At the sametime, the sputtering particles are adhered on the substrate surfacewhich is activated by the exposure to the vacuum ultraviolet light sothat they are adhered firmly on the substrate surface. Therefore, it ispossible to give a surface of substrates, such as resinous substratescomposed of carbon-containing materials, the mechanical, physical andchemical characteristics such as the dent resistance, wettability, waterrepellency, damage resistance, lipophilicity, gas-barrier property,depositability, adhesiveness, scratch resistance, ozone resistance,yellowing preventiveness, grooming resistance, dirt resistance,hydrophilicity, mildewproofness, frictional property, stainability,printability, writability, electrical conductivity and lubricativeproperty. Simultaneously, it is possible to improve the adhesiveness offilms such as paintings and platings.

[0009] In a second aspect of the present invention, the substrate isplaced on a side of a laser beam-irradiating surface of a targetmaterial, the surface of the substrate is exposed to a vacuumultraviolet light which is generated by irradiating the target materialwith a laser beam, and particles, which sputter from the targetmaterial, are deposited on the surface of the substrate.

[0010] When the target material is irradiated with the laser beam, ahigh-temperature plasma is formed on a surface of the target material,and the vacuum ultraviolet light is thereby generated from the plasma.The resultant vacuum ultraviolet light is adsorbed by carbon-containingmaterials with a high absorptivity. When the surface of the substrate isexposed to the vacuum ultraviolet light, the p-shell electrons, theouter shell electrons in carbon atoms, are excited or ionized at thesubstrate surface so that the molecular bonds are destroyed to activatethe substrate surface composed of a carbon-containing material. On theother hand, at the surface of the target material, which is heatedwithin the plasma or by the plasma, particles such as neutral atoms,ions and clusters are formed, and sputter from the inside of the plasmaor from the surface of the target material at velocities as high as thesonic-velocity level. Accordingly, the surface of the substrate isactivated by the exposure to the vacuum ultraviolet light, and iscovered with the sputtering particles immediately thereafter.Consequently, the particles are adhered firmly on the surface of thesubstrate.

[0011] As for the target material, depending on the applications of thesubstrate with the thus reformed surface, it is possible to use metals,such as Cu, Al, Ti, Cr, Pt, Au, Ag, Zr, Mg, Ni, Fe, Co, Zn, Sn, W andBe, semiconductors, ceramics, carbon and composite materials of these.

[0012] In a third aspect of the present invention, the substrate isplaced on a side of a laser beam-irradiating surface of a targetmaterial in a container, and the target material placed in the containeris irradiated with a laser beam. Note that the container can desirablybe vacuum containers.

[0013] Since the vacuum ultraviolet light which is generated from theplasma is hardly absorbed by air in the vacuum container, it is possibleto satisfactorily activate a surface of substrates composed ofcarbon-containing materials. Moreover, since the sputtering particles,which sputter from the inside of the plasma or from the surface of thetarget material at velocities as high as the sonic-velocity level, arenot blocked or decelerated by atmospheric molecules, which are presentbetween the substrate and the target material, it is possible tosecurely deposit the sputtering particles on the substrate surface whichis activated by the exposure to the vacuum ultraviolet light.

[0014] In a fourth aspect of the present invention, the target materialis irradiated with a laser beam in a shielding gas atmosphere or whilesupplying a shielding gas between the substrate and the target materialat least.

[0015] A vacuum ultraviolet light is generated in a plasma in ashielding gas atmosphere. When the shielding gas is supplied, the vacuumultraviolet light is inhibited from being absorbed by air. Accordingly,it is possible to favorably activate the substrate surface.

[0016] In a fifth aspect of the present invention, the target materialis irradiated with a laser beam in a shielding gas atmosphere or whilesupplying a shielding gas between the substrate and the target materialat least.

[0017] When a hydrogen gas, and the like, which absorb the vacuumultraviolet light remarkably less, are used as the shielding gas, it ispossible to securely pass and generate the vacuum ultraviolet light, forexample, a vacuum ultraviolet light whose wavelength falls in a range offrom 50 to 100 nm, in air, and to reliably expose the substrate surfaceto the vacuum ultraviolet light.

[0018] In a sixth aspect of the present invention, the substrate iscomposed of a transparent substrate in which a laser beam can transmit,and the target material is irradiated with a laser beam through thetransparent substrate.

[0019] When the target material is irradiated with the laser beamthrough the transparent substrate, it is possible to use lenses whosefocal length is short in order to focus the laser beam on the targetmaterial. Accordingly, it is possible to carry out the irradiation witha large F value. Consequently, it is possible to reform a surface oftransparent substrates such as transparent resinous films in anatmosphere close to air. Moreover, since the transparent substrate withthe thus reformed surface is good in terms of the characteristics suchas the heat-ray reflection or absorption property, the gas-barrierproperty and the electromagnetic-shielding property, it is possible toactually carry out coating such as heat-ray protective films,electromagnetic-shielding films and gas-barrier layers with the presentsurface reforming process.

[0020] In a seventh aspect of the present invention, the laser beam is apulse laser beam whose pulse duration falls in a range of from 100picoseconds to 100 nanoseconds.

[0021] With the arrangement, it is possible to inhibit the transparentsubstrate from being damaged or denatured even when the laser beamtransmits through the transparent substrate. The pulse duration canfurther preferably fall in a range of from 100 picoseconds to 20nanoseconds, furthermore preferably from 1 nanoseconds to 10nanoseconds.

[0022] In an eighth aspect of the present invention, the conditions ofirradiating the target material with the laser beam are set so as togenerate a vacuum ultraviolet light, whose wavelength falls in a rangeof from 50 to 100 nm, from the target material.

[0023] Since the vacuum ultraviolet light whose wavelength falls in arange of from 50 to 100 nm is absorbed by carbon-containing materialswith a high absorptivity, the molecular bonds in carbon-containingmaterials are destroyed effectively so that the substrate surface isactivated securely. The wavelength can further preferably fall in arange of from 50 to 80 nm.

[0024] In a ninth aspect of the present invention, the irradiationintensity of the laser beam is set so as to fall in a range of from 10⁶to 10¹² W/cm².

[0025] When the irradiation intensity of the laser beam is set withinthe aforementioned range, it is possible to securely generate the vacuumultraviolet light whose wavelength falls in a range of from 50 to 100 nmwhich is absorbed by carbon-containing materials with a highabsorptivity. When the substrate surface is exposed to the ultravioletlight, the molecular bonds in carbon-containing materials are destroyedeffectively so that the substrate surface is activated securely. Theirradiation intensity can further preferably fall in a range of from 10⁹to 10¹¹ W/cm², furthermore preferably from 4×10⁹ to 8×10¹⁰ W/cm².

[0026] In a tenth aspect of the present invention, a substrate isprovided with a reformed superficial portion, and comprises: a substratecomposed of a carbon-containing material; a surface exposed to a vacuumultraviolet light; and particles deposited on a part of the surface atleast.

[0027] In the present reformed substrate, the particles are deposited onthe surface of the substrate composed of a carbon-containing materialwhich is activated by the exposure to the vacuum ultraviolet light.Accordingly, the deposited particles are firmly adhered on the surfaceof the substrate. Consequently, the surface of the substrate is providedwith the mechanical, physical and chemical characteristics such as thedent resistance, wettability, water repellency, damage resistance,lipophilicity, gas-barrier property, depositability, adhesiveness,scratch resistance, ozone resistance, yellowing preventiveness, groomingresistance, dirt resistance, hydrophilicity, mildewproofness, frictionalproperty, stainability, printability, writability, electricalconductivity and lubricative property. Simultaneously, the surface ofthe substrate is good in terms of the adhesiveness of films such aspaintings and platings.

[0028] In an eleventh aspect of the present invention, an apparatus isadapted for reforming a surface of a substrate composed of acarbon-containing material, and comprises: means for exposing thesurface of the substrate to a vacuum ultraviolet light; and means forgenerating sputtering particles which are to be deposited on the surfaceof the substrate exposed to the vacuum ultraviolet light.

[0029] The surface of the substrate composed of a carbon-containingmaterial is exposed to the vacuum ultraviolet light, whichcarbon-containing materials absorb with a high absorptivity, by theexposing means. The sputtering particles are generated by the generatingmeans, and are simultaneously adhered firmly on the substrate surfacewhich is activated by the exposure to the vacuum ultraviolet light.

[0030] In a twelfth aspect of the present invention, the exposure of thesubstrate to the vacuum ultraviolet light by the exposing means and thegeneration of the sputtering particles by the generating means arecarried out simultaneously.

[0031] When the exposure of the substrate to the vacuum ultravioletlight and the generation of the sputtering particles are carried outsimultaneously, the sputtering particles are deposited immediately afterthe substrate surface is activated by the exposure to the vacuumultraviolet light. Accordingly, it is possible to firmly adhere theparticles on the substrate surface securely.

[0032] In a thirteenth aspect of the present invention, an apparatus isadapted for reforming a surface of a substrate composed of acarbon-containing material, and comprises: a laser beam-generatingdevice for generating a laser beam; a target material; a substrateplaced on a side of a laser beam-irradiating surface of the targetmaterial, and composed of a carbon-containing material; and optics forfocusing the laser beam generated by the laser beam-generating device onthe target material, wherein the surface of the substrate is exposed toa vacuum ultraviolet light, which is generated by irradiating the targetmaterial with the laser beam through the optics, and particles, whichsputter from a surface of the target material irradiated with the laserbeam, are deposited on the surface of the substrate.

[0033] In a fourteenth aspect of the present invention, the apparatusfurther comprises a container in which the substrate is placed on theside of the laser beam-irradiating surface of the target material,wherein the laser beam generated by the laser beam-generating device isled into the container through the optics, and is focused on the targetmaterial. Note that the container can desirably be vacuum containers.

[0034] In a fifteenth aspect of the present invention, the apparatusfurther comprises means for supplying a shielding gas, wherein thetarget material is irradiated with the laser beam through the opticswhile supplying the shielding gas between the substrate and the targetmaterial at least with the supplying means.

[0035] When a helium gas, and the like, which absorb vacuum ultravioletlights less, is used as the shielding gas and the substrate is exposedto the vacuum ultraviolet light in such a shielding gas atmosphere, itis not necessary to place substrates to be subjected to the processingin any vacuum container. Accordingly, not limited to methods in whichsubstrates are batch processed by a unit of predetermined pieces, it ispossible to continuously carry out surface reforming treatments, or tocarry out surface reforming treatments onto large-sized component parts,with the present surface reforming apparatus.

[0036] In a sixteenth aspect of the present invention, the apparatusfurther comprises a processing chamber in which a shielding gasatmosphere is kept and the substrate is placed on the side of the laserbeam-irradiating surface of the target material, wherein the surface ofthe substrate is exposed to a vacuum ultraviolet light, which isgenerated by irradiating the target material with the laser beam throughthe optics, and particles, which sputter from a surface of the targetmaterial irradiated with the laser beam, are deposited on the surface ofthe substrate within the processing chamber.

[0037] In the processing chamber in which the shielding gas atmosphereis kept, the shielding gas atmosphere inhibits the air from absorbingthe vacuum ultraviolet light. Accordingly, it is possible tosatisfactorily activate the substrate surface.

[0038] In a seventeenth aspect of the present invention, the apparatusfurther comprises a preparatory chamber disposed between an externalspace and the processing chamber to communicate with the processingchamber, wherein the substrate is brought in into the processing chamberfrom the external space through the preparatory chamber, and is takenout from the processing chamber to the external space through thepreparatory chamber.

[0039] Since the substrate is brought in into the processing chamber andis taken out from the processing chamber through the preparatorychamber, it is possible to securely keep the shielding gas atmospherewithin the processing chamber. Moreover, since the substrate is broughtin into the processing chamber from the external space through thepreparatory chamber, the brought-in substrate is subjected to a surfacereforming treatment, and the processed substrate is taken out from theprocessing chamber to the external space through the preparatorychamber, it is possible to achieve production systems which can carryout surface reforming treatments onto a large volume of substratescontinuously and efficiently.

[0040] In an eighteenth aspect of the present invention, a gas whosespecific gravity is smaller than that of air is used as the shieldinggas, and the processing chamber is disposed at an upper position withrespect to the preparatory chamber.

[0041] With the arrangement, it is possible to localize the shieldinggas within the processing chamber. Accordingly, it is possible tosecurely keep the shielding gas atmosphere within the processingchamber.

[0042] In a nineteenth aspect of the present invention, a gas whosespecific gravity is larger than that of air is used as the shieldinggas, and the processing chamber is disposed at a lower position withrespect to the preparatory chamber.

[0043] With the arrangement, it is possible to localize the shieldinggas within the processing chamber. Accordingly, it is possible tosecurely keep the shielding gas atmosphere within the processingchamber.

[0044] In a twentieth aspect of the present invention, the apparatusfurther comprises an openable-and-closable partition wall disposedbetween the processing chamber and the preparatory chamber and/orbetween the external space and the preparatory chamber, wherein thepartition wall is opened or closed to communicate the processing chamberwith or separate it from the preparatory chamber and/or to communicatethe external space with or separate it from the preparatory chamber.

[0045] With the arrangement, even when the shielding gas is likely tomix with air due to the reasons that the specific gravity of theshielding gas is close to that of air, and the like, it is possible tosecurely keep the shielding gas atmosphere within the processingchamber.

[0046] In a twenty-first aspect of the present invention, the shieldinggas is at least one member selected from the group consisting of ahydrogen gas, a helium gas, a neon gas, an argon gas and mixture gasescomposed of arbitrary combination of the gases.

[0047] In a twenty-second aspect of the present invention, the substrateis composed of a transparent substrate in which a laser beam cantransmit, and the laser beam-generating device irradiates the targetmaterial with a laser beam through the transparent substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

[0048] A more complete appreciation of the present invention and many ofits advantages will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings and detailedspecification, all of which forms a part of the disclosure:

[0049]FIG. 1 is a schematic construction diagram for illustrating anoverall construction of a substrate surface reforming apparatus in aFirst Preferred Embodiment according to the present invention;

[0050]FIG. 2a-c are diagrams for schematically illustrating a structureof a resinous-substrate surface, wherein:

[0051]FIG. 2a shows when the resinous-substrate surface was subjectedthe exposure to a vacuum ultraviolet light and the deposition ofsputtering particles;

[0052]FIG. 2b shows when the resinous-substrate surface was subjectedthe exposure to a vacuum ultraviolet light alone; and

[0053]FIG. 2c shows when the resinous-substrate surface was subjectedthe deposition of sputtering particles alone;

[0054]FIG. 3 is a graph for illustrating the results of a photoelectronspectroscopic analysis which was carried out onto samples of Example No.1, in which a polyethylene film was subjected to the exposure to avacuum ultraviolet light exposure and the deposition of sputteringparticles, and samples of comparative examples;

[0055]FIG. 4 is a schematic construction diagram for illustrating anoverall construction of a substrate surface reforming apparatus in aSecond Preferred Embodiment according to the present invention;

[0056]FIG. 5 is a graph for illustrating the intensity distribution ofthe spectrum of a vacuum ultraviolet light which was generated from acopper target;

[0057]FIG. 6 is a graph for illustrating the transmission characteristicof a polytetrafluoroethylene resin with respect to a vacuum ultravioletlight;

[0058]FIG. 7 concerns Example No. 2, and is a traced image for showingthe result of an observation on a silicon wafer with a mirror groundedsurface, on which particles sputtered from a copper target werecollected, with a scanning electron microscope;

[0059]FIG. 8a-b concern Example No. 2, and are traced images in which afilm, formed on a silicone-rubber substrate and composed of copperparticles, was viewed, wherein:

[0060]FIG. 8a is a traced image viewed before assessing theadhesiveness; and

[0061]FIG. 8b is a traced image viewed after assessing the adhesiveness;

[0062]FIG. 9 concerns Example No. 2, and is a traced image for showingthe result of an observation on a film, which was formed on apolytetrafluoroethylene resinous substrate and was composed of finecopper particles, with a scanning electron microscope;

[0063]FIG. 10a-b concern Example No. 2, and are traced images in which afilm, formed on a polytetrafluoroethylene resinous substrate andcomposed of copper particles, was viewed, wherein:

[0064]FIG. 10a is a traced image viewed before assessing theadhesiveness; and

[0065]FIG. 10b is a traced image viewed after assessing theadhesiveness;

[0066]FIG. 11 is a schematic construction diagram for illustrating anoverall construction of a substrate surface reforming apparatus in aThird Preferred Embodiment according to the present invention;

[0067]FIG. 12 is a graph for illustrating the transmissioncharacteristic of a vacuum ultraviolet light in a 1 atm helium gas;

[0068]FIG. 13 is a schematic construction diagram for illustrating anoverall construction of a substrate surface reforming apparatus in aFourth Preferred Embodiment according to the present invention;

[0069]FIG. 14 concerns Example No. 4, and is a traced image in which analumina film, formed on a polyethylene film, was viewed;

[0070]FIG. 15 is a schematic construction diagram for illustrating anoverall construction of a substrate surface reforming apparatus in aFifth Preferred Embodiment according to the present invention; and

[0071]FIG. 16 is a schematic construction diagram for illustrating aconstruction of a laser abrasion device in the Fifth PreferredEmbodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0072] Having generally described the present invention, a furtherunderstanding can be obtained by reference to the specific preferredembodiments which are provided herein for the purpose of illustrationonly and not intended to limit the scope of the appended claims.

[0073] Hereinafter, preferred embodiments according to the presentinvention will be described in detail. The respective preferredembodiments embody a process for reforming a surface of a substrate, areformed substrate and an apparatus for the same according to thepresent invention.

First Preferred Embodiment

[0074] First of all, a substrate surface reforming apparatus 1 in aFirst Preferred Embodiment according to the present invention will bedescribed with reference to FIG. 1.

[0075]FIG. 1 is a schematic construction diagram for illustrating anoverall construction of the substrate surface reforming apparatus 1. Thesubstrate surface reforming apparatus 1 comprises a vacuum ultravioletlight-generating device 2, an electron beam deposition device 3, and acontainer 4 in which a resinous substrate S is placed. The resinoussubstrate S is to be subjected to a surface reforming treatment. Notethat the vacuum ultraviolet light-generating device 2 makes the exposingmeans according to the present invention, and the electron beamdeposition device 3 makes the generating means, respectively.

[0076] The resinous substrate S can be substrates composed of a varietyof resinous materials, such polytetrafluoroethylene, silicone rubber,epoxy resin, polypropylene, polyethylene and polyethylene terephthalate.However, the object of the surface reforming is not limited to resinoussubstrates. It is possible to subject substrates composed ofcarbon-containing material shaving carbon-carbon bonds, preferablyorganic materials, further preferably resinous materials, to the surfacereforming. Note that the resinous substrate S corresponds to thesubstrate composed of a carbon-containing material according to thepresent invention.

[0077] The vacuum ultraviolet light-generating device 2 is a lamp whichcan emit a vacuum ultraviolet light (or referred to as vacuumultraviolet radiation whenever appropriate) whose wavelength falls in arange of from 50 to 100 nm. It is placed so that the resinous substrateS, which is placed within the vacuumed container 4, is exposed to thevacuum ultraviolet light. Note that the ultraviolet lights whosewavelength is 200 nm or less are referred to as the vacuum ultravioletlight in the present invention.

[0078] The electron beam deposition device 3 can sputter particles,which are composed of metals, such as Cu, Al, Ti, Cr, Pt, Au, Ag, Zr,Mg, Ni, Fe, Co, Zn, Sn, W and Be, semiconductors, ceramics, carbon andcomposite materials of these, depending on the applications of theresinous substrate S.

[0079] Hereinafter, the operations -and advantages, which are effectedwhen the surface reforming treatment of the resinous substrate S iscarried out with the substrate surface reforming apparatus 1, will bedescribed with reference to FIG. 2a.

[0080] When the vacuum ultraviolet light-generating device 2 generatesthe vacuum ultraviolet light whose wavelength falls in a range of from50 to 100 nm, the resinous substrate S, which is placed within thevacuumed container 4, is exposed to the vacuum ultraviolet light. Then,on a surface of the resinous substrate S, the separation occurs betweenthe electron-hole pairs and the excitons (see (2 a-1) in FIG. 2a). Thesurface goes through the non-relaxation process in which the pelectrons, being the outer shell electrons in the carbon atoms, areexcited or ionized (see (2 a-2) in FIG. 2a). Finally, the bonds betweenthe main chains and side chains of the resinous structure are broken,and thereby the electrons, which have been involved in the bonds, areemitted to form activated end groups (seen (2 a-3) in FIG. 2a).

[0081] Subsequently, when the sputtering particles, such as neutralatoms, ions and clusters, which are generated by the electron beamdeposition device 3, are deposited on the surface of the resinoussubstrate S, which is activated by the exposure to the vacuumultraviolet light, the activated end groups are fixed to produce a statein which the activated end groups and the sputtering particles (orabrator particles) coexist. Thus, the electrons are inhibited from beingsupplied to the surface or being excited inversely so that the activatedresinous surface is sustained for a long period of time (see (2 a-4) inFIG. 2).

[0082] Hence, the resinous substrate S, having the reformed surfacewhich is produced by the above-described process according to the FirstPreferred Embodiment, is provided with the mechanical, physical andchemical characteristics such as the dent resistance, wettability, waterrepellency, damage resistance, lipophilicity, gas-barrier property,depositability, adhesiveness, scratch resistance, ozone resistance,yellowing preventiveness, grooming resistance, dirt resistance,hydrophilicity, mildewproofness, frictional property, stainability,printability, writability and lubricative property. Simultaneously, iteffects an advantage in that it is good in terms of the adhesiveness offilms such as paintings and platings.

[0083] For comparison, other superficial structures of the resinoussubstrate S will be hereinafter described with reference to FIGS. 2b and2 c. In the case of FIG. 2b, the resinous substrate S is exposed to thevacuum ultraviolet light only. In the case of FIG. 2c, it is subjectedto the deposition of the sputtering particles alone.

[0084] When the resinous substrate S is exposed to the vacuumultraviolet light only, on a surface of the resinous substrate S, theseparation occurs between the electron-hole pairs and the excitons (see(2 b-1) in FIG. 2b). The surface goes through the non-relaxation processin which the p electrons, being the outer shell electrons in the carbonatoms, are excited or ionized (see (2 b-2) in FIG. 2b). Finally, thebonds between the main chains and side chains of the resinous structureare broken, and thereby the electrons, which have been involved in thebonds, are emitted to form activated end groups once (seen (2 b-3) inFIG. 2b). However, when the surface is left as it is, the p electronsare put back to the original state (i.e., the relaxation process),because the electrons are supplied from the inside or outside, orbecause they are excited inversely. Thus, the activated end groupsdisappear from the surface of the resinous substrate S. Eventually, thesurface of the resinous substrate S returns back to the deactivatedstate (see (2 b-4) in FIG. 2b).

[0085] On the other hand, when the resinous substrate S is subjected tothe deposition of the sputtering particles alone, only the physicaldeposition of the sputtering particles occurs on the surface of theresinous substrate S (see (2 c-2) in FIG. 2c) in the relaxation satefree from the activated end groups (see (2 c-1) in FIG. 2c). Thus, noactivated resinous surface is formed at all.

[0086] As described above, it is seen that the activate surface can besustained only when the substrate, such as resinous substrates composedof carbon-containing materials, is subjected to both the exposure to thevacuum ultraviolet light and the deposition of the sputtering particles.

Second Preferred Embodiment

[0087] Hereinafter, a substrate surface reforming apparatus 11 in aSecond Preferred Embodiment according to the present invention will bedescribed with reference to FIG. 4.

[0088]FIG. 4 is a schematic construction diagram for illustrating anoverall construction of the substrate surface reforming apparatus 11.The substrate surface reforming apparatus 11 comprises a YAG laserdevice 12, a condenser 13, a vacuum container 14 in which a resinoussubstrate S is placed as the substrate, and a target driving system 15which holds a target material 15 a. The resinous substrate S is to besubjected to a surface reforming treatment, and is composed of acarbon-containing material. Note that the YAG laser device 12 makes thelaser beam-generating device according to the present invention, thecondenser 13 makes the optical member, and the YAG laser device 12 andtarget driving system 15 make the exposing means and generating means,respectively.

[0089] Since the resinous substrate S is the same as the resinoussubstrate in the above-described First Preferred Embodiment, it will notbe described herein in detail. Moreover, note that, as described in theFirst Preferred Embodiment, the objects to be processed are not limitedto resinous substrates, and that they can be substrates which comprisecarbon-containing materials.

[0090] The YAG laser device 12 is a known laser beam-generating device.It is disposed so as to emit a laser beam toward the target material 15a placed in the vacuum container 14.

[0091] The condenser 13 is disposed between the YAG laser device 12 andthe vacuum container 14. It is an optical member which leads the laserbeam generated from the YAG laser device 12 into the vacuum container 14through a glass window 14 a of the vacuum container 14 and focuses thelaser beam on the target material 15 a. In the condenser 13, the size orrefractive index of the lens is designed so that the laser beam isfocused with a predetermined irradiation intensity on the targetmaterial 15 a. Moreover, the irradiation intensity can preferably becontrolled so that the plasma generated from the target material 15 agenerates a vacuum ultraviolet light having a wavelength which isabsorbed by resinous substrates with a high absorptivity. Specifically,the irradiation intensity of the laser beam can preferably fall in arange of from 10⁶ to 10¹² W/cm².

[0092] The vacuum container 14 is a container in which vacuum is kept.It accommodates the resinous substrate S, an object to be processed, andthe target driving system 15 therein. In the vacuum container 14, theresinous substrate S is placed on a side of a laser beam-irradiatingsurface of the target material 15 a which is held by the target drivingsystem 15. Moreover, the vacuum container 14 is provided with the window14 a. The window 14 a enables the laser beam generated from the YAGlaser device 12 to enter into the vacuum container 14, and is composedof a transparent material such as glass.

[0093] The target driving system 15 comprises the continuousstrip-shaped target material 15 a, and a pair rollers 15 b which feedthe target material 15 a to a laser beam-irradiating position and windthe target material 15 a to accommodate after the target material 15 ais irradiated with the laser beam. As for the target material 15 a,depending on the applications of the resinous substrate S, it ispossible to use metals, such as Cu, Al, Ti, Cr, Pt, Au, Ag, Zr, Mg, Ni,Fe, Co, Zn, Sn, W and Be, semiconductors, ceramics, carbon and compositematerials of these.

[0094] Hereinafter, the operations and advantages, which are effectedwhen the surface reforming treatment of the resinous substrate S iscarried out with the substrate surface reforming apparatus 11, will bedescribed.

[0095] When the YAG laser device 12 generates the laser beam, thecondenser 13 leads the laser beam into the vacuum container 14 throughthe window 14 a and focuses it on the target material 15 a. When thetarget material 15 a is irradiated with the laser beam, ahigh-temperature plasma is formed on a surface of the target material 15a. The temperature of the plasma is controlled so that the vacuumultraviolet light whose wavelength falls in a range of from 50 to 100 nmis generated. The vacuum ultraviolet light having the wavelength isabsorbed by resinous materials with a high absorptivity. Accordingly,when the surface of the resinous substrate S is exposed to the vacuumultraviolet light, the molecular bonds in the surface are destroyed bythe vacuum ultraviolet light so that the resinous surface is activated.

[0096] On the other hand, on the surface of the target material 15 awhich is heated within the plasma or by the plasma, neutral atoms, ionsand clusters are formed. They sputter from the surface of the targetmaterial 15 a at velocities as high as the sonic-velocity level.

[0097] Accordingly, the surface of the resinous substrate S, which isplaced adjacent to the plasma formed on the surface of the targetmaterial 15 a, is activated by the exposure to the vacuum ultravioletlight, and immediately thereafter the sputtering particles adhere on thesurface of the resinous substrate S. Consequently, the sputteringparticles firmly adhere on the surface of the resinous substrate S. As aresult, the electrons are inhibited from being supplied to the surfaceor being excited inversely so that the activated resinous surface issustained for a long period of time. Note that the phenomena in theabove process take place successively in the same manner as described inthe First Preferred Embodiment.

[0098] Hence, the resinous substrate S, having the reformed surfacewhich is produced by the above-described process according to the SecondPreferred Embodiment, is provided with the mechanical, physical andchemical characteristics such as the dent resistance, wettability, waterrepellency, damage resistance, lipophilicity, gas-barrier property,depositability, adhesiveness, scratch resistance, ozone resistance,yellowing preventiveness, grooming resistance, dirt resistance,hydrophilicity, mildewproofness, frictional property, stainability,printability, writability and lubricative property. Simultaneously, iteffects an advantage in that it is good in terms of the adhesiveness offilms such as paintings and platings.

[0099] Moreover, in the Second Preferred Embodiment, the exposure of theresinous substrate S to the vacuum ultraviolet light and the generationof the sputtering particles are achieved simultaneously by emitting thelaser beam onto the target material 15 a. Thus, it is possible toremarkably simplify the entire construction of the apparatus. (ThirdPreferred Embodiment)

[0100] Hereinafter, a substrate surface reforming apparatus 21 in aThird Preferred Embodiment according to the present invention will bedescribed with reference to FIG. 11.

[0101]FIG. 11 is a schematic construction diagram for illustrating anoverall construction of the substrate surface reforming apparatus 21.The substrate surface reforming apparatus 21 comprises a YAG laserdevice 22, a first optical member 23, an abrasion gun 24, and a targetmaterial 28. Note that the YAG laser device 22 makes the laserbeam-generating device according to the present invention, and the YAGlaser device 22 and target material 28 make the exposing means andgenerating means, respectively.

[0102] Since a resinous substrate S is the same as the resinoussubstrate in the above-described First Preferred Embodiment, it will notbe described herein in detail. Moreover, note that, as described in theFirst Preferred Embodiment, the objects to be processed are not limitedto resinous substrates, and that they can be substrates which comprisecarbon-containing materials.

[0103] The YAG laser device 22 is a known laser beam-generating device.It is disposed so as to emit a laser beam (L) toward a half mirror 23 aof the first optical member 23.

[0104] The first optical member 23 comprises the half mirror 23 a and areflector mirror 23 b, and leads the laser beam, emitted by the YAGlaser device 22, into the abrasion gun 24 while dividing the laser beaminto two parts. Specifically, the YAG laser device 22 emits the laserbeam (L) onto the half mirror 23 a, and the laser beam (L) enters thehalf mirror 23 a at an incident angle of about 45 degrees. Thus, theincident beam is reflected by half of the beam intensity at the halfmirror 23 a, and is led into the abrasion gun 24 (hereinafter referredto as a first path L1). On the other hand, the other half of theincident beam transmits through the half mirror 23 a, and enters thereflector mirror 23 b at an incident angle of about 45 degrees. Thus,the other half of the incident beam is reflected totally at thereflector mirror 23 b, and is led into the abrasion gun 24 in parallelto the laser beam following the first path L1 (hereinafter referred toas a second path L2).

[0105] The abrasion gun 24 comprises a case 25, a second optical member26, a gas nozzle 27 which sprays a helium gas, and a target material 28.Note that the first optical member 23 and second optical member 26 makethe optical member according to the present invention, and the gasnozzle 27 makes the supplying means.

[0106] The case 25 is provided with an incident opening 25 a and anemission opening 25 b. The incident opening 25 a is formed at thetrailing end of the case 25, and lets the laser beam coming from thefirst optical member 23 enter into the case 25. The emission opening 25b is formed at the leading end of the case 25, and lets particlessputtering from the target material 28 discharge toward the resinoussubstrate S to be subjected to a surface reforming treatment. Moreover,the case 25 accommodates the second optical member 26, gas nozzle 27 andtarget material 28 therein.

[0107] The second optical member 26 comprises a first condenser 26 a, afirst reflector mirror 26 b, a second condenser 26 c, and a secondreflector mirror 26 d. The first condenser 26 a focuses the laser beamfollowing the first path Ll. The first reflector mirror 26 b reflectsthe laser beam which is focused by the first condenser 26 a, and emitsit onto a surface of the target material 28, surface which faces theemission opening 25 b. The second condenser 26 c focuses the laser beamfollowing the second path L2. The second reflector mirror 26 d reflectsthe laser beam which is focused by the second condenser 26 c, and emitsit onto the surface of the target material 28, surface which faces theemission opening 25 b.

[0108] In the first and second condensers 26 a, 26 c, the size orrefractive index of the lenses are designed so that the laser beam isfocused with a predetermined irradiation intensity on the targetmaterial 28. Moreover, the irradiation intensity can preferably becontrolled so that the plasma generated from the target material 28generates a vacuum ultraviolet light having a wavelength which isabsorbed by resinous substrates with a high absorptivity. Specifically,the irradiation intensity of the laser beam can preferably fall in arange of from 10⁶ to 10¹² W/cm².

[0109] The gas nozzle 27 is a gas spraying nozzle for supplying a heliumgas between the target material 28 and the resinous substrate S. Thehelium gas is a shielding gas for shielding the vacuum ultraviolet lightand sputtering particles which are generated from the target material28. The gas nozzle 27 is connected with a not-shown gas tank whichstores the helium gas, and is placed on a rear side with respect to thetarget material 28 in the case 25 (i.e., on the left hand side in FIG.11), and its spraying opening 27 a is directed toward the emissionopening 25 b of the case 25.

[0110]FIG. 12 illustrates the transmission characteristic of the vacuumultraviolet light in a 1 atm helium gas. As can be seen from FIG. 12,the transmissivity of the vacuum ultraviolet light whose wavelengthfalls in a range of from 50 to 100 nm is 100% substantially in thehelium gas, that is, it is absorbed extremely less by the helium gas.Thus, it can be seen that it is possible to expose the substrate S tothe vacuum ultraviolet light in the helium gas atmosphere.

[0111] The target material 28 is a disk-shaped member or a rod-shapedmember whose cross section is shaped as a circle, and comprises amaterial which can sputter particles upon being irradiated with a laserbeam. It is placed in such a direction that it crosses orthogonally tothe first and second paths L1, L2 (i.e., in the direction perpendicularto the page surface of FIG. 11). It is rotated by a not-shown targetdriving system.

[0112] Hereinafter, the operations and advantages, which are effectedwhen the surface reforming treatment of the resinous substrate S iscarried out with the substrate surface reforming apparatus 21, will bedescribed.

[0113] When the laser beam is generated from the YAG laser device 22,the incident laser beam is reflected by half of the beam intensity atthe half mirror 23 a, and is led to the first path L1 in the case 25 ofthe abrasion gun 24 through the incident opening 25 a. The laser beamfollowing the first path L1 is focused by the first condenser 26 a, andis reflected at the first reflector mirror 26 b. Thus, the laser beamfollowing the first path L1 is emitted onto the surface of the targetmaterial 28, surface which faces the emission opening 25 b. On the otherhand, the other half of the incident laser beam, which transmits throughthe half mirror 23 a, is reflected at the reflector mirror 23 b, and isled to the second path L2 in the case 25 of the abrasion gun 24 throughthe incident opening 25 a. The laser beam following the second path L2is focused by the second condenser 26 c, and is reflected at the secondreflector mirror 26 d. Thus, the laser beam following the second path L2is emitted onto the surface of the target material 28, surface whichfaces the emission opening 25 b. Therefore, the laser beams, introducedby way of the first and second paths L1, L2, are emitted to the surfaceof the target material 28 with different angles, and are superimposedthereon. Accordingly, the surface of the target material 28, which facesthe emission opening 25 b, is irradiated by the laser beam with thedesired beam intensity without deflection.

[0114] Moreover, simultaneously with the emission of the laser beam, thegas nozzle 27 sprays the helium gas toward the emission opening 25 bfrom the rear side of the target material 28. Thus, the space betweenthe target material 28 and the resinous substrate S, which is placed toface the emission opening 25 b, is kept to the helium gas atmospherewhich absorbs the vacuum ultraviolet light extremely less.

[0115] When the target material 28 is irradiated with the laser beam inthe helium gas atmosphere, a high-temperature plasma is formed on thesurface of the target material 28. The temperature of the plasma iscontrolled so that the vacuum ultraviolet light whose wavelength fallsin a range of from 50 to 100 nm is generated. In this instance, when thehelium gas is supplied as the shielding gas, the vacuum ultravioletlight is inhibited from being absorbed by air. Moreover, the vacuumultraviolet light having the wavelength is absorbed by resinousmaterials with a high absorptivity. Accordingly, when the surface of theresinous substrate S is exposed to the vacuum ultraviolet light, themolecular bonds in the resinous surface are destroyed by the vacuumultraviolet light so that the resinous surface is activated.

[0116] On the other hand, on the surface of the target material 28 whichis heated within the plasma or by the plasma, neutral atoms, ions andclusters are formed. They sputter from within the plasma or from thesurface of the target material 28 at velocities as high as thesonic-velocity level.

[0117] Accordingly, the surface of the resinous substrate S, which isplaced to face the emission opening 25 b, is activated by the exposureto the vacuum ultraviolet light, and immediately thereafter thesputtering particles adhere on the surface of the resinous substrate S.Consequently, the sputtering particles firmly adhere on the surface ofthe resinous substrate S. As a result, the electrons are inhibited frombeing supplied to the surface or being excited inversely so that theactivated resinous surface is sustained for a long period of time. Notethat the phenomena in the above process take place successively in thesame manner as described in the First Preferred Embodiment.

[0118] Moreover, since the helium gas, which absorbs the vacuumultraviolet light less, is used as the shielding gas so that theresinous substrate S is exposed to the vacuum ultraviolet light in thehelium gas atmosphere, it is not necessary to place the resinoussubstrate S, an object to be processed, in a vacuum container.Therefore, not limited to the processes in which the resinous substrateis batch processed by a unit of predetermined pieces, the ThirdPreferred Embodiment can carry out surface reforming treatmentscontinuously, and can subject a large-sized component parts to surfacereforming treatments.

[0119] In addition, the vacuum ultraviolet light is generated from theplasma formed on the target material 28 more in the perpendiculardirection, and the sputtering particles are emitted from the surface ofthe target material 28 more in the perpendicular direction. Accordingly,it is possible to substantially simultaneously carry out exposing theresinous substrate S to the vacuum ultraviolet light and adhering thesputtering particles onto the resinous substrate S in one and onlydirection.

[0120] Note that the present invention is not limited to theabove-described preferred embodiments. It is possible to give a varietyof modifications to the preferred embodiments as far as they fall withinthe spirit or scope of the present invention.

[0121] For example, the optical system for focusing the laser beam onthe target material 28 is not limited to the above-described arrangementmade by the first and second optical members 23, 26. It can be achievedby a diversity of embodiments.

[0122] Moreover, in the Third Preferred Embodiment, the helium gas isused in order to inhibit the vacuum ultraviolet light from beingabsorbed by air. It is possible to use a hydrogen gas, a neon gas or anargon gas as the shielding gas. In short, it is possible to use gaseswhich absorb the vacuum ultraviolet light less as the shielding gas.

Fourth Preferred Embodiment

[0123] Hereinafter, a substrate surface reforming apparatus 31 in aFourth Preferred Embodiment according to the present invention will bedescribed with reference to FIG. 13.

[0124]FIG. 13 is a schematic construction diagram for illustrating anoverall construction of the substrate surface reforming apparatus 31.The substrate surface reforming apparatus 31 comprises a pulse YAG laserdevice 32, a condenser 33, and a target material 38. Moreover, in thesurface reforming apparatus 31, the constituent elements, the pulse YAGlaser device 32, the condenser 33, a transparent resinous film S′ andthe target material 38 are placed in this order linearly. Note that thepulse YAG laser device 32 makes the laser beam-generating deviceaccording to the present invention, and the pulse YAG laser device 32and target material 38 make the exposing means and generating means,respectively.

[0125] As the transparent resinous film S′, being an object to besubjected to a surface reforming treatment, it is possible to usetransparent substrates which comprise transparent polyethylene films,for example. However, objects to be surface-reformed are not limited totransparentpolyethylene films. As far as transparent substrates comprisecarbon-containing materials having carbon-carbon bonds, furtherpreferably organic materials, furthermore preferably resinous materials,and can transmit laser beams, they can be objects to besurface-reformed. Note that the transparent resinous film S′ makes thetransparent substrate according to the present invention.

[0126] The pulse YAG laser device 32 is a known pulse laserbeam-generating device, and generates a laser beam whose pulse widthfalls in a range of from 100 picoseconds to 100 nanoseconds. The pulseYAG laser device 32 is disposed on an opposite side with respect to thetarget material 28 with the transparent resinous film S′ interposedtherebetween. The pulse YAG laser device 32 is placed so as to emit thelaser beam toward the target material 38 through the condenser 33 andtransparent resinous film S′.

[0127] The condenser 33 is a convex lens for focusing the pulse laserbeam which is emitted from the pulse YAG laser device 32 on the targetmaterial 38 with a proper size. In the condenser 33, the size orrefractive index of the lens is designed so that the pulse laserbeam isfocused with a predetermined irradiation intensity on the targetmaterial 38. Moreover, the irradiation intensity can preferably becontrolled so that a plasma generated from the target material 38generates a vacuum ultraviolet light having a wavelength which isabsorbed by the transparent resinous film S′ with a high absorptivity.Specifically, the irradiation intensity of the laser beam can preferablyfall in a range of from 10⁶ to 10¹² W/cm².

[0128] The target material 38 comprises a material which sputtersparticles from the surface upon being irradiated with the pulse laserbeam. It is disposed on an opposite side with respect to the pulse YAGlaser device 32 with the transparent resinous film S′ interposedtherebetween. The pulse laser beam generated from the pulse YAG laserdevice 32 transmits through the transparent resinous film S′ while beingfocused by the condenser 33. Accordingly, the target material 38 isirradiated with the pulse laser beam.

[0129] Hereinafter, the operations and advantages, which are effectedwhen the surface reforming treatment of the transparent resinoussubstrate S′ is carried out with the substrate surface reformingapparatus 31, will be described.

[0130] When the pulse laser beam whose pulse width falls in a range offrom 100 picoseconds to 100 nanoseconds is generated from the pulse YAGlaser device 32, the pulse laser beam transmits through the transparentresinous film S′ while being focused by the condenser 33. Accordingly,the target material 38 is irradiated with the pulse laser beam. In thisinstance, since the transparent resinous film S′ is transparent, it isnot damaged or denatured at all when the pulse laser beam transmitstherethrough.

[0131] When the target material 38 is irradiated with the pulse laserbeam, a high-temperature plasma is formed on the surface of the targetmaterial 38. The temperature of the plasma is controlled so that thevacuum ultraviolet light whose wavelength falls in a range of from 50 to100 nm is generated. Moreover, the vacuum ultraviolet light having thewavelength is absorbed by resinous materials with a high absorptivity.Accordingly, when the surface of the transparent resinous film S′ isexposed to the vacuum ultraviolet light, the molecular bonds in theresinous surface are destroyed by the vacuum ultraviolet light so thatthe resinous surface is activated.

[0132] On the other hand, on the surface of the target material 38 whichis heated within the plasma or by the plasma, neutral atoms, ions andclusters are formed. They sputter from within the plasma or from thesurface of the target material 38 at velocities as high as thesonic-velocity level.

[0133] Accordingly, the surface of the transparent resinous film S′,which is placed to face the target material 38, is activated by theexposure to the vacuum ultraviolet light, and immediately thereafter thesputtering particles adhere on the surface of the transparent resinousfilm S′. Consequently, the sputtering particles firmly adhere on thesurface of the transparent resinous films'. As a result, the electronsare inhibited from being supplied to the surface or being excitedinversely so that the activated resinous surface is sustained for a longperiod of time. Note that the phenomena in the above process take placesuccessively in the same manner as described in the First PreferredEmbodiment.

[0134] Moreover, when the target material 38 is irradiated with thepulse laser beam through the transparent resinous film S′, it ispossible to use lenses whose focal length is short, for example, whosefocal length is about 40 mm, for focusing the pulse laser beam on thetarget material 38, and accordingly to emit the laser beam with a largeF value. Consequently, not limited to vacuumed state, it is possible tosurface-reform the transparent resinous film S′ even under reducedpressures, or in atmospheres close to air, or preferably in shieldinggas atmospheres.

[0135] In addition, since the pulse laser beam whose pulse width fallsin a range of from 100 picoseconds to 100 nanoseconds is used, thetransparent resinous film S′ is not damaged or denatured at all when thepulse laser beam transmits therethrough.

[0136] Note that the present invention is not limited to theabove-described preferred embodiments. It is possible to give a varietyof modifications to the preferred embodiments as far as they fall withinthe spirit or scope of the present invention.

[0137] For example, the above-described preferred embodiments use theYAG laser devices to generate the laser beam. However, it does notmatter at all when they use the other types of laser beam-generatingdevices.

[0138] Moreover, the target materials can be formed as a variety ofshapes such as rod shapes, tape shapes and disk shapes.

Fifth Preferred Embodiment

[0139] Hereinafter, a substrate surface reforming apparatus 41 in aFifth Preferred Embodiment according to the present invention will bedescribed with reference to FIG. 15.

[0140]FIG. 15 is a schematic construction diagram for illustrating anoverall construction of the substrate surface reforming apparatus 41.The substrate surface reforming apparatus 41 comprises an abrasiondevice 42, a processing chamber 43, and a preparatory chamber 44. In theprocessing chamber 43, the abrasion device 42 is placed, and a resinoussubstrate S is subjected to a surface reforming treatment. Thepreparatory chamber 44 is disposed so as to communicate with theprocessing chamber 43.

[0141] Since the resinous substrate S is the same as the resinoussubstrate in the above-described First Preferred Embodiment, it will notbe described herein in detail. Moreover, note that, as described in theFirst Preferred Embodiment, the objects to be processed are not limitedto resinous substrates, and that they can be substrates which comprisecarbon-containing materials.

[0142] In the processing chamber 43, a space is formed in which ashielding gas atmosphere is kept, and the abrasion device 42 and theresinous substrate S, an objected to be processed, are placed. To makethe shielding gas atmosphere, gases are used which absorb the vacuumultraviolet light less. For example, it is possible to use at least onemember selected from the group consisting of a hydrogen gas, a heliumgas, a neon gas and an argon gas. Additionally, it is possible to usemixture gases comprising arbitrary combinations of these gases.

[0143] The preparatory chamber 44 is a space which is formed between theexternal space and the processing chamber 43 so as to communicate withthe processing chamber 43. The resinous substrate S to be processed isbrought in into the processing chamber from the external space throughthe preparatory chamber 44. After the abrasion device 42 carries out asurface reforming treatment onto the resinous substrate S in theprocessing chamber 43, the resinous substrate S is taken out from theprocessing chamber 43 to the external space through the preparatorychamber 44.

[0144] When the shielding gas atmosphere in the processing chamber 43 ismade by using gases, whose specific gravity is smaller than that of air,such as a hydrogen gas and a helium gas, it is preferable to dispose theprocessing chamber 43 at an upper position with respect to thepreparatory chamber 44 as illustrated in FIG. 15. Specifically, in thesurface reforming apparatus 41, the hydrogen gas whose specific gravityis smaller than that of air localizes in the processing chamber 43 whichis disposed at a relatively higher position. On the contrary, the airwhose specific resistance is larger than that of the hydrogen gaslocalizes in the preparatory chamber 44 which is disposed at arelatively lower position. Moreover, since the preparatory chamber 44 isdisposed between the processing chamber 43 and the external space, theair is inhibited from coming into the atmosphere in the processingchamber 43 from the external space. Therefore, the shielding gasatmosphere, such as the hydrogen gas atmosphere, is kept in theprocessing chamber 43.

[0145] On the other hand, when the shielding gas atmosphere in theprocessing chamber 43 is made by using gases, whose specific gravity islarger than that of air, such as an argon gas, it is preferable todispose the processing chamber 43 at a lower position with respect tothe preparatory chamber 44, though such a processing chamber 43 is notshown. Specifically, in the surface reforming apparatus 41, the argongas whose specific gravity is larger than that of air localizes in theprocessing chamber 43 which is disposed at a relatively lower position.On the contrary, the air whose specific resistance is smaller than thatof the argon gas localizes in the preparatory chamber 44 which isdisposed at a relatively higher position. Moreover, since thepreparatory chamber 44 is disposed between the processing chamber 43 andthe external space, the air is inhibited from coming into the atmospherein the processing chamber 43 from the external space. Therefore, theshielding gas atmosphere, such as the argon gas atmosphere, is kept inthe processing chamber 43.

[0146] Accordingly, as the abrasion device 42, it is possible to use adevice, which is free from a gas nozzle for spraying a shielding gassuch as a helium gas, for example, a device as illustrated in FIG. 16.

[0147] Hereinafter, the operations and advantages, which are effectedwhen the surface reforming treatment of the resinous substrate S iscarried out with the substrate surface reforming apparatus 41, will bedescribed. Note the following descriptions are made on the assumptionthat the processing chamber 43 is put into a helium gas atmosphere.

[0148] First of all, the resinous substrate S, an object to beprocessed, is brought in into the preparatory chamber 44 from theexternal space under an atmospheric pressure, and is transferred towardthe processing chamber 43. As the resinous substrate S is transferred inthe preparatory chamber 44, the atmosphere around the resinous substrateS gradually approaches the helium gas atmosphere from the atmosphericpressure. When the resinous substrate S is brought in into theprocessing chamber 43 in which the helium gas atmosphere is kept, it issubjected to a laser abrasion treatment, or a surface reformingtreatment described below, with the abrasion device 42.

[0149] Thereafter, the resinous substrate S whose surface is reformed bythe laser abrasion treatment is taken out from the processing chamber43, in which the helium gas atmosphere is kept, to the external spaceunder the atmospheric pressure through the preparatory chamber 44.

[0150] Since the resinous substrate S is exposed to the vacuumultraviolet light in the helium gas atmosphere which absorbs the vacuumultraviolet light less, it is not necessary to place the resinoussubstrate S, an object to be processed, in a vacuum container.Therefore, not limited to the processes in which the resinous substrateis batch processed by a unit of predetermined pieces, the FifthPreferred Embodiment can carry out surface reforming treatmentscontinuously, and can subject a large-sized component parts to surfacereforming treatments.

[0151] Moreover, a plurality of the resinous substrates S can besuccessively brought in into the processing chamber 43 from the externalspace through the preparatory chamber 44, and can be subjected to thesurface reforming treatment. After carrying out the surface reformingtreatment, the resinous substrates S can be successively taken out fromthe processing chamber 43 to the external space through the preparatorychamber 44. Hence, in accordance with the Fifth Preferred Embodiment, itis possible to achieve a production system which can subject a largevolume of resinous substrates S to surface reforming treatmentscontinuously and efficiently.

[0152] Note that the present invention is not limited to theabove-described preferred embodiments. It is possible to give a varietyof modifications to the preferred embodiments as far as they fall withinthe spirit or scope of the present invention.

[0153] For example, the optical system for focusing the laser beam onthe target material is not limited to the above-described arrangementmade by the first and second optical members. It can be achieved by adiversity of embodiments.

[0154] Moreover, in the Fifth Preferred Embodiment, the processingchamber 43 always communicates with the preparatory chamber 44. However,it is possible to add the following arrangement. For instance, asindicated with the broken line in FIG. 15, openable-and-closablepartition walls 45 can be disposed between the processing chamber 43 andthe preparatory chamber 44 and/or between the external space and thepreparatory chamber 44. The partition walls 45 can be opened or closedto communicate the processing chamber 43 with or separate it from thepreparatory chamber 44 and/or to communicate the external space with orseparate it from the preparatory chamber 44. Specifically, the partitionwalls 45 can be opened to communicate the external surface with thepreparatory chamber 44 and to communicate the preparatory chamber 44with the processing chamber 43 in the following cases alone: i.e., whenthe resinous substrate S, an object to be processed, is brought in intothe preparatory chamber 44 from the external space; when it is broughtin into the processing chamber 43 from the preparatory chamber; when itis taken out from the processing chamber 43 to the preparatory chamber44; and when it is taken out from the preparatory chamber 44 to theexternal space. Thus, when the resinous substrate S is not transferred,the partition wall is closed to separate the external space from thepreparatory chamber 44 and separate the preparatory chamber 44 from theprocessing chamber 43. With such an arrangement, even when gases, forexample, an argon gas which is likely to mix with air because itsspecific gravity is close to air, is used to make the shielding gasatmosphere, the air is inhibited from coming into the atmosphere in theprocessing chamber 43 from the external space. Therefore, it is possibleto securely keep the shielding gas atmosphere in the processing chamber43.

[0155] In addition, when it is required to carryout the laser abrasiontreatment under reduced pressures, it is possible to depressurize bycarry out differential evacuation in the processing chamber 43 or aroundthe leading end of an abrasion gun 423 shown in FIG. 16.

[0156] Note that an abrasion device can be placed in the processingchamber 43, abrasion device which has the identical arrangements withthose of the surface reforming apparatus 21 in the Second PreferredEmbodiment as illustrated in FIG. 11, and that the abrasion treatmentcan be carried out while supplying a shielding gas between the resinoussubstrate S and a target material 426 shown in FIG. 16.

EXPERIMENTAL EXAMPLES

[0157] Experiments were conducted in accordance with the above-describedpreferred embodiments. Hereinafter, the respective experimental exampleswill be described with reference to the drawings.

Example No. 1

[0158] To begin with, a first experiment (i.e., Example No. 1) wasconducted according to the First Preferred Embodiment. Example No. 1will be hereinafter described.

[0159] A polyethylene film was used as a sample of the resinoussubstrate S. In the vacuumed container 4, the polyethylene film wasexposed to the vacuum ultraviolet light by the vacuum ultravioletlight-generating device 2, and sputtering particles resulting fromalumina were adhered on the polyethylene film. The resulting sampleswere analyzed by a photoelectron spectroscopic analysis. As comparativeexamples, the following samples were prepared: a sample which wasexposed to the vacuum ultraviolet light alone; a sample on which onlythe sputtering particles resulting from alumina adhered; and a sample, apolyethylene film itself which was not processed at all. The respectivecomparative examples were analyzed likewise by a photoelectronspectroscopic analysis. FIG. 3 illustrates the results of thephotoelectron spectroscopic analysis, and shows spectra of the 1selectrons in carbon. The horizontal axis designates the bond energy(eV), and the vertical axis designates the intensity. As can be seenfrom FIG. 3, in the sample subjected to the exposure to the vacuumultraviolet light and the adhesion to the sputtering particles, thespectra, resulting from the bonds with oxygen such as C—O, C═O and CO₂,were shifted with respect to the spectra of the not-processedcomparative sample. On the other hand, in the comparative samplesubjected to the exposure to the vacuum ultraviolet light alone and thecomparative sample subjected to the adhesion of the sputtering particlesonly, the observed spectra were substantially the same as those of thenon-processed comparative sample. Thus, it is understood that theactivated surface (or activated end groups) can be formed and sustainedonly when both the exposure to the vacuum ultraviolet light and theadhesion of the sputtering particles are carried out.

[0160] Subsequently, the above-describe sample and comparative exampleswere painted, and were assessed for the adhesiveness of the resultingpaint films. As a result, high adhesive performance was exhibited onlyin the sample which was subjected to the exposure to the vacuumultraviolet light as well as the adhesion of the sputtering particles.

Example No. 2

[0161] Further, a second experiment (i.e., Example No. 2) was conductedin accordance with the Second Preferred Embodiment. Example No. 2 willbe hereinafter described.

[0162] In Example No. 2, the following YAG laser device 12 was used inthe surface reforming apparatus 11 whose arrangements are illustrated inFIG. 4. The used YAG laser device 12 generated a laser beam which was ahigher harmonic wave having a frequency twice as large as thefundamental frequency, whose energy per pulse was 1 J, and whose pulsewidth was 7 nanoseconds. As the target material 15 a, a copper targetwas used which was composed of copper. The laser beam generated from theYAG laser device 12 was led into the vacuum container 14 by thecondenser 13, and was focused on the copper target with a diameter of800 micrometers approximately. Thus, the copper target was irradiated bythe laser beam with an irradiation intensity of 108 W/cm². When thecopper target was irradiated with the laser beam, a high-temperatureplasma was generated on the copper target. As a result, the copperplasma generated a vacuum ultraviolet light whose spectrum had awavelength-intensity distribution as illustrated in FIG. 5. Note thatFIG. 5 was illustrated based on the values measured by a cue plate. Ascan be seen from FIG. 5, it is understood that a continuous spectrumwith a high brightness was observed in the wavelength falling in a rangeof from 50 to 100 nm which is absorbed by resins with a highabsorptivity, and in the wavelengths around the specific wavelength.

[0163] Further, the transmission characteristic ofpolytetrafluoroethylene, one of resins, with respect to the vacuumultraviolet light will be described with reference to the graphillustrated in FIG. 6. A polytetrafluoroethylene film was examined forthe transmission characteristic. The polytetrafluoroethylene comprisedpolyterafluoroethylene in an amount of 2.2% by weight, and was 0.2micrometers thick. From the graph illustrated in FIG. 6, it isunderstood the polytetrafluoroethylene film exhibited the minimumtransmissivity of 10⁻⁸ with respect to the vacuum ultraviolet lightwhose wavelength was around 60 nm, and exhibited the sharply reducedtrasmissivities (i.e., increased absorptivities) with respect to thevacuum ultraviolet lights whose wavelengths fell around 60 nm. Thephenomena depend on the absorption characteristic of carbon, one of thecomponents of tetrafluoroethylene. From FIG. 6, it is seen that thevacuum ultraviolet light whose wavelength falls in a range of from 50 to100 nm is absorbed by tetrafluoroethylene with a high absorptivity.

[0164] Furthermore, the sputtering particles, which were generated fromthe copper target of the surface reforming apparatus in the SecondPreferred Embodiment, were collected with a silicon wafer. They wereobserved with a scanning electron microscope, and the image was tracedas illustrated in FIG. 7. As illustrated in FIG. 7, copper fineparticles (dots illustrated in white), whose particle diameters were afew micrometers or less, adhered on the silicon wafer.

[0165] Moreover, a silicone rubber substrate was subjected to thesurface reforming treatment in accordance with the Second PreferredEmbodiment. After the surface reforming treatment, an adhesive tape wasapplied to the film which was formed on a surface of the silicone rubbersubstrate and was composed of the copper fine particles. Then, theadhesive tape was torn off from the silicone rubber substrate manually,thereby assessing the adhesiveness of the fine copper particles onto thesilicone rubber substrate. As a result, the fine copper particles hardlyadhered onto the adhesive tape. FIG. 8a is a traced image of the film,which was formed on a surface of the silicone rubber substrate and wascomposed of the copper fine particles, before the adhesivenessassessment test. FIG. 8b is a traced image of the same film after theadhesiveness assessment test. From FIG. 8a and FIG. 8b, it isappreciated that the film was not come off from the silicone rubbersubstrate though cracks (portions illustrated in white) grow slightly bythe adhesiveness assessment test.

[0166] In addition, a polytetrafluoroethylene resinous substrate wasprepared as the resinous substrate S, and was subjected to the surfacereforming treatment in accordance with the Second Preferred Embodimentfor 1 minutes. FIG. 9 is a traced image when the polytetrafluoroethyleneresinous substrate surface, which was subjected to the exposure to thevacuum ultraviolet light whose wavelength fell around 60 nm and theadhesion of the copper fine particles substantially simultaneously, wasobserved with a scanning electron microscope. From FIG. 9, it is seenthat finely textured fine copper particles adhered on thepolytetrafluoroethylene resinous substrate.

[0167] Subsequently, an adhesive tape was applied to the film which wasformed on a surface of the polytetrafluoroethylene resinous substrateafter the surface reforming treatment, and which was composed of thecopper fine particles. Thereafter, the adhesive tape was torn off fromthe polytetrafluoroethylene resinous substrate manually, therebyassessing the adhesiveness of the fine copper particles onto thepolytetrafluoroethylene resinous substrate. As a result, the fine copperparticles hardly adhered onto the adhesive tape. FIG. 10a is a tracedimage of the film, which was formed on a surface of thepolytetrafluoroethylene resinous substrate and was composed of thecopper fine particles, before the adhesiveness assessment test. FIG. 10bis a traced image of the same film after the adhesiveness assessmenttest. From FIG. 10a and FIG. 10b, it is appreciated that the film wasnot come off from the polytetrafluoroethylene resinous substrate, thoughcracks (portions illustrated in white) grow slightly by the adhesivenessassessment test.

[0168] For comparison, a polytetrafluoroethylene resinous substrate towhich copper particles were adhered by an electron beam deposition, anda polytetrafluoroethylene resinous substrate to which copper particleswere adhered by an electron beam deposition after the exposure to thevacuum ultraviolet light were prepared, and were subjected to theadhesiveness assessment test with the adhesive tape, respectively. As aresult, in both of them, most of the copper particles had adhered to theadhesive tape.

[0169] Moreover, an epoxy resin, polypropylene, polyethylene,polyethylene terephthalate were used as the material of the substrate,and the resinous substrates were subjected to the surface reformingtreatment in accordance with the Second Preferred Embodiment. As aresult, all of them produced favorable outcomes in the same manner asExample No. 2 described above. In addition, even when aluminum was usedas the target material instead of copper, the processed resinoussubstrates produced satisfactory results similarly to the cases wherethe copper target material was used.

Example No. 3

[0170] Moreover, a third experiment (i.e., Example No. 3) was conductedin accordance with the Third Preferred Embodiment. Example No. 3 will behereinafter described.

[0171] In Example No. 3, the following YAG laser device 22 was used inthe surface reforming apparatus 21 whose arrangements are illustrated inFIG. 11. The used YAG laser device 22 generated a laser beam which was ahigher harmonic wave having a frequency twice as large as thefundamental frequency, whose energy per pulse was 1 J, and whose pulsewidth was 7 nanoseconds. As the target material 28, a copper tape targetwas used which is composed of a polymer film having a thickness of 30micrometers and a copper tape having a thickness of 15 micrometers andbonded on the polymer film. The laser beam generated from the YAG laserdevice 22 was focused by the first and second optical members 23, 26 onthe copper tape target 28 with a diameter of 800 micrometersapproximately. Thus, the copper tape target 28 was irradiated by thelaser beam with an irradiation intensity of 2.5×10⁸ W/cm². When thecopper tape target 28 was irradiated with the laser beam, ahigh-temperature plasma was generated on the copper tape target 28. As aresult, the copper plasma generated a vacuum ultraviolet light spectrum.Simultaneously with the generation of the vacuum ultraviolet light, thegas nozzle 27 supplied a helium gas from the rear side of the coppertape target 28 toward the emission opening 25 b, and thereby turns thespace between the copper tape target 28 and the resinous substrate Sinto a helium gas atmosphere.

[0172] A polyethylene terephathalate (PET) resinous substrate S wasplaced at a position from 5 mm to 1 cm away from the emission opening 25b disposed at the leading end of the abrasion gun 24. Then, the coppertape target 28 was abraded with the surface reforming apparatus 21according to the Third Preferred Embodiment for 5 minutes. Note that,although the accessible distances of the sputtering particles dependgreatly on the material qualities and sizes in 1 atm helium gasatmosphere, it is possible to design the accessible distances to a fewcentimeters or more depending on specific conditions.

[0173] When the thickness of the film, which was formed on the PETresinous substrate S by the above-described process and which wascomposed of copper particles, was measured with a step meter, it wasfound to be about 800 nm. Moreover, a tearing test was carried out byapplying an adhesive tape onto the copper particles which were abradedon the PET resinous substrate S and by manually tearing off the adhesivetape therefrom. As a result, the copper particles were hardly torn offfrom the PET resinous substrate S.

Example No. 4

[0174] In addition, a fourth experiment (i.e., Example No. 4) wasconducted in accordance with the Third Preferred Embodiment. Example No.4 will be hereinafter described.

[0175] In Example No. 4, the following YAG laser device 32 was used inthe surface reforming apparatus 31 whose arrangements are illustrated inFIG. 13. The used YAG laser device 32 generated a laser beam whoseenergy per pulse was 1 J, and whose pulse width was 7 nanoseconds. Asthe transparent resinous film S′, a polyethylene film was used whosethickness was 50 micrometers. As the target material 38, alumina wasused. In a helium gas atmosphere under a reduced pressure to 1/10 atm,the laser beam generated from the YAG laser device 32 was focused by anear-focal condenser 33 having a focal length of 40 mm on the coppertarget with a diameter of 2 mm approximately. Thus, the target material38 was irradiated with the laser beam. When the target material 38 wasirradiated with the laser beam, a high-temperature plasma was generatedon the target material 38 which was composed of alumina. As a result,the alumina plasma generated a vacuum ultraviolet spectrum. When a laserabrasion operation was carried out with the surface reforming apparatus31 according to the Fourth Preferred Embodiment for 3 minutes, aluminawas deposited uniformly on the transparent resinous substrate S′ whichwas composed of the polyethylene film. In the traced image illustratedin FIG. 14, the portions shown in white are portions where the aluminawas deposited. The squared portion shown in gray at the center of thedrawing was a portion which was covered with a glass cover for measuringthe thickness of the alumina. Note that the size of the squared portionwas actually a square whose side was 10 mm each. As a result of thethickness measurement, the thickness was found to be 200 nmapproximately. Note that the thickness of some 2 on missufficed forusing the film in the application to gas-barrier films. Accordingly,when the transparent resinous film S′ is fed at a feeding rate of some15 cm/minute, it is possible to coat a uniform alumina film over wideareas.

[0176] Having now fully described the present invention, it will beapparent to one of ordinary skill in the art that many changes andmodifications can be made thereto without departing from the spirit orscope of the present invention as set forth herein including theappended claims.

What is claimed is:
 1. A process for reforming a surface of a substratecomposed of a carbon-containing material, comprising the step of:exposing a surface of a substrate to a vacuum ultraviolet light, anddepositing sputtering particles on the surface of the substrate.
 2. Theprocess set forth in claim 1, wherein the substrate is placed on a sideof a laser beam-irradiating surface of a target material, the surface ofthe substrate is exposed to a vacuum ultraviolet light which isgenerated by irradiating the target material with a laser beam, andparticles, which sputter from the target material, are deposited on thesurface of the substrate.
 3. The process set forth in claim 2, whereinthe substrate is placed on a side of a laser beam-irradiating surface ofa target material in a container, and the target material placed in thecontainer is irradiated with a laser beam.
 4. The process set forth inclaim 2, wherein the target material is irradiated with a laser beam ina shielding gas atmosphere or while supplying a shielding gas betweenthe substrate and the target material at least.
 5. The process set forthin claim 4, wherein at least one member, selected from the groupconsisting of a hydrogen gas, a helium gas, a neon gas and an argon gas,mixture gases composed of arbitrary combination of the gases, or mixturegases in which the gases are major components, is used as the shieldinggas.
 6. The process set forth in claim 2, wherein the substrate iscomposed of a transparent substrate in which a laser beam can transmit,and the target material is irradiated with a laser beam through thetransparent substrate.
 7. The process set forth in claim 2, wherein thelaser beam is a pulse laser beam whose pulse duration falls in a rangeof from 100 picoseconds to 100 nanoseconds.
 8. The process set forth inclaim 2, wherein the conditions of irradiating the target material withthe laser beam are set so as to generate a vacuum ultraviolet light,whose wavelength falls in a range of from 50 to 100 nm, from the targetmaterial.
 9. The process set forth in claim 2, wherein the irradiationintensity of the laser beam is set so as to fall in a range of from 10⁶to 10¹² W/cm².
 10. An apparatus for reforming a surface of a substratecomposed of a carbon-containing material, comprising: means for exposingthe surface of the substrate to a vacuum ultraviolet light; and meansfor generating sputtering particles which are to be deposited on thesurface of the substrate exposed to the vacuum ultraviolet light. 11.The apparatus set forth in claim 10, wherein the exposure of thesubstrate to the vacuum ultraviolet light by the exposing means and thegeneration of the sputtering particles by the generating means arecarried out simultaneously.
 12. An apparatus for reforming a surface ofa substrate composed of a carbon-containing material, comprising: alaser beam-generating device for generating a laser beam; a targetmaterial; a substrate placed on a side of a laser beam-irradiatingsurface of the target material, and composed of a carbon-containingmaterial; and an optical member for focusing the laser beam generated bythe laser beam-generating device on the target material, wherein thesurface of the substrate is exposed to a vacuum ultraviolet light, whichis generated by irradiating the target material with the laser beamthrough the optical member, and particles, which sputter from a surfaceof the target material irradiated with the laser beam, are deposited onthe surface of the substrate.
 13. The apparatus set forth in claim 12further comprising a container in which the substrate is placed on theside of the laser beam-irradiating surface of the target material,wherein the laser beam generated by the laser beam-generating device isled into the container through the optical member, and is focused on thetarget material.
 14. The apparatus set forth in claim 12 furthercomprising means for supplying a shielding gas, wherein the targetmaterial is irradiated with the laser beam through the optical memberwhile supplying the shielding gas between the substrate and the targetmaterial at least with the supplying means.
 15. The apparatus set forthin claim 12 further comprising a processing chamber in which a shieldinggas atmosphere is kept and the substrate is placed on the side of thelaser beam-irradiating surface of the target material, wherein thesurface of the substrate is exposed to a vacuum ultraviolet light, whichis generated by irradiating the target material with the laser beamthrough the optical member, and particles, which sputter from a surfaceof the target material irradiated with the laser beam, are deposited onthe surface of the substrate within the processing chamber.
 16. Theapparatus set forth in claim 15 further comprising a preparatory chamberdisposed between an external space and the processing chamber tocommunicate with the processing chamber, wherein the substrate isbrought in into the processing chamber from the external space throughthe preparatory chamber, and is taken out from the processing chamber tothe external space through the preparatory chamber.
 17. The apparatusset forth in claim 16, wherein a gas whose specific gravity is smallerthan that of air is used as the shielding gas, and the processingchamber is disposed at an upper position with respect to the preparatorychamber.
 18. The apparatus set forth in claim 16 further comprising anopenable-and-closable partition wall disposed between the processingchamber and the preparatory chamber and/or between the external spaceand the preparatory chamber, wherein the partition wall is opened orclosed to communicate the processing chamber with or separate it fromthe preparatory chamber and/or to communicate the external space with orseparate it from the preparatory chamber.
 19. The apparatus set forth inclaim 14, wherein the shielding gas is at least one member selected fromthe group consisting of a hydrogen gas, a helium gas, a neon gas, anargon gas and mixture gases composed of arbitrary combination of thegases.
 20. The apparatus set forth in claim 12, wherein the substrate iscomposed of a transparent substrate in which a laser beam can transmit,and the laser beam-generating device irradiates the target material witha laser beam through the transparent substrate.